EECE 363 Quiz 4B 2008 Solutions

# Also find the operating mode of the transistor and

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Unformatted text preview: m) = 20 μm -3- 3) For the enhancement-type PMOS circuit below, find the values for VD and ID. Also find the operating mode of the transistor and quantitatively justify your answer. Assume ⎛W ⎞ k p ' ⎜ ⎟ = 0.3125 mA/V2, Vt = −1 V, and VA=∞. (Suggested time to spend: 15 min) ⎝L⎠ (6 points) 5V − VSD = 5V + VDS = (1.6 kΩ)⋅ID Assume saturation: ID = (1/2)kp’(W/L)(VGS − Vt)2 = (1/2)(0.3125mA/V2)[−5V − (−1V)]2 = 2.5 mA ⏐VDS⏐=5V − (1.6 kΩ)(2.5 mA) = 1 V ⏐VGS⏐− ⏐Vt⏐= 5V − 1 V = 4 V ⏐VDS⏐< ⏐VGS⏐− ⏐Vt⏐ (Not in saturation) Assume triode: 5V + VDS = (1.6 kΩ){(0.3125mA/V2)[(−5V − (−1V))VDS − (1/2)VDS2]} or 5V + VDS = −2VDS − 0.25VDS2 or (VDS + 2V)(VDS + 10V) = 0 then VDS = −2 V, or −10 V Triode when VDS = −2 V (fulfilling ⏐VDS⏐<...
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## This document was uploaded on 02/16/2014 for the course EECE 363 at University of British Columbia.

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